Arista Networks Inc used rival Cisco Systems Inc's network device technology in its ethernet switches without permission, a U.S. trade judge ruled on Friday, handing Cisco yet another win in a sprawling legal battle over patents between the two companies. The judge, MaryJoan McNamara of the U.S. International Trade Commission in Washington, said that Arista had infringed two patents owned by Cisco. The ruling, which must be reviewed by the full commission over the next few months, could lead to an order banning the import of Arista's products into the United States.